How do I get an object to rotate around a different axis based on the raycasts hit angle?

So, I'm working on a building game where instead of it just being blocks, there's other shapes too like ramps, spheres, etc. But I'm having an issue getting objects to rotate according to the surface you're looking at. For example, I'm looking at the wall and hit "R" it will rotate the block on the axis that's perpendicular to the face, Right now it will rotate only on the axis that's perpendicular to the floor. If my question isn't clear enough, here's a drawing that may hopefully explain it a little better.